1. Field of the Invention
This invention relates generally to construction techniques employing prefabricated modules, and particularly to the construction of the veil section of hyperbolic natural draft cooling towers.
2. Description of the Prior Art
Hyperbolic natural draft cooling towers are generally, but not necessarily exclusively, constructed in conjunction with fossil fuel, nuclear energy, and the like, electrical generating power plants and similar facilities. It is known to construct up draft towers, cross draft towers, and other known flow systems within a structure in the form of a hyperbolic veil, with only the lower portion of the towers, that portion below and including the lintel beam, being effected to achieve the different flow systems.
The current, or conventional, method of constructing these hyperbolic veils is to use cast-in-place concrete, heavily reinforced with steel reinforcing bars. The veil sections are, from their hyperboloid form, thick at the bottom thereof and taper into thin sections at the throat of the tower, subsequently increasing in thickness from the throat to the top of the structure.
One of the most expensive and time-consuming tasks in building a veil by the conventional method is in the formwork for the cast-in-place concrete. The forms must be built on both sides of the wall of the veil, and the constantly changing circumference of the structure and thickness of the wall requires complicated modifications of the forms and tedious layout work. Further, this expensive operation is not a permanent part of the end product, but only a means to the end.
The following prior patents are believed pertinent to this invention:
______________________________________ 1,153,205 September 14, 1915 1,954,891 April 17, 1934 2,177,264 October 24, 1939 2,664,740 January 5, 1954 2,794,336 June 4, 1967 3,216,163 November 9, 1965 3,300,942 January 31, 1967 3,300,943 January 31, 1967 3,322,409 May 30, 1967 3,618,277 November 9, 1971 3,764,121 October 9, 1973 3,779,523 December 18, 1973 3,801,076 April 2, 1974 3,834,681 September 10, 1974 797,413 (Great Britain) July 2, 1958 ______________________________________